Reducing flow noise in a refrigerant expansion valve

ABSTRACT

A combination thermally responsive refrigerant expansion valve with integral electrically operated inlet shutoff valve having an inlet shutoff valve seat surrounded by a flow diffuser which eliminates undesirable flow noise. In the preferred embodiment the diffuser comprises a plurality of radially extending flow channels formed adjacent the inlet shutoff valve seat integrally in a one-piece valve seat member.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to refrigerant expansion valves ofthe type typically operated by a thermally responsive sensor such as afluid filled capsule and which employ in combination an electricallyoperated shutoff valve at the inlet of the expansion valve. Valves ofthis type are commonly employed in motor vehicle passenger compartmentair conditioning systems where high ambient thermal load gradients areencountered and rapid changes in refrigerant flow are often required tomaintain passenger comfort.

[0002] Heretofore, such combination thermally operated expansion valveswith an electrically operated inlet shutoff valve have experiencedproblems of flow noise and particularly high frequency noisecharacterized as “hissing” which has been found to be unacceptable fromthe standpoint of the vehicle occupants.

[0003] Referring to FIG. 3, a known combination thermal expansion valveand electrically operated inlet shutoff valve is indicated generally at1 and includes a solenoid operator indicated generally at 2 attached tothe valve block of a thermal expansion valve indicated generally at 3.The valve block 4 has an inlet 5 and an outlet 6 with a expansion valvemember 7 therebetween which is moveable by an operating member 8. Itwill be understood that the operating member 8 is moved by a thermallyresponsible sensing unit or capsule (not shown) as is well known in theart of automotive refrigerant expansion valves.

[0004] A riser passage 9 communicates the flow from inlet 5 through aspider clip 10 and the inner periphery of a sealing washer 11 whichretains a valve seat member 12 in the block. Valve seat member 12defines an inlet valve seat 13 against which is moved a shutoff valvemember 14, which in turn is moved by an armature 15 forming part of thesolenoid operator 2 which includes a solenoid coil 16 surrounding thearmature 15. A pilot passage 18 is formed in the shutoff valve member 18with a pilot valve member 19 seated on the upper end thereof. The priorart valve assembly shown in FIG. 3 has been found to exhibit aprohibitive amount of flow noise which is generated in the region of thespider clip 10 and washer 11 which are registered against the shoulderformed in the armature guide 17.

[0005] Accordingly, it has been desired to find a way or means ofproviding a refrigerant expansion valve operated by a thermallyresponsive member in combination with an electrically operated inletshutoff valve which is relatively low in manufacturing cost, easy toassemble and reduces undesirable flow noise and particularly hissing. Ithas further been desired to provide such a combination valve which hasreduced flow noise and which is sufficiently low in manufacturing costto be suitable for high volume mass production of motor vehicle airconditioning systems.

BRIEF SUMMARY OF THE INVENTION

[0006] The present invention provides a combination refrigerantexpansion valve, of the type intended to be operated by a thermallyresponsive unit, in combination with an electrically operated inletshutoff valve. The valve assembly of the present invention employs anexpansion valve member operating against a valve seat in a valve block;and, the valve member is retained on the valve seat and moved withrespect to the valve seat by an operating rod or member of the typeintended to be connected to a thermally responsive sensing capsule.

[0007] A shutoff valve seat member is received over the retainer for theexpansion valve; and, a shutoff valve member is disposed thereagainstand moved with respect to the shutoff valve seat by the armature of asolenoid attached to the valve body. The shutoff valve seat has adiffuser disposed adjacent and surrounding its valve seat, which servesto direct the flow to the valve seat and reduce flow noise. In thepreferred embodiment, the diffuser comprises a plurality of radiallyoutwardly extending flow channels which direct the flow from a riserpassage in the valve block communicating with the valve inlet. In thepresently preferred practice the valve seat member and diffuser channelsare formed integrally in a one piece, preferably cup-shaped member.

[0008] The present invention thus provides a unique and novelconstruction for an electrically operated inlet shutoff valve incombination with a thermal expansion valve and which is relatively lowin manufacturing costs, easy to assemble and eliminates undesirable flownoise.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a cross-section of the combination valve assembly of thepresent invention showing the expansion valve and solenoid operatedinlet shutoff valve;

[0010]FIG. 2 is an enlarged perspective view of the inlet shutoff valveseat of the embodiment of FIG. 1; and,

[0011]FIG. 3 is a view similar to FIG. 1 of a prior art valve assembly.

DETAILED DESCRIPTION OF THE INVENTION

[0012] Referring to FIG. 1, the combination valve assembly of thepresent invention is indicated generally at 20 and includes anelectrically energizable solenoid operator indicated generally at 22attached to an expansion valve indicated generally at 24. The valve 24has a valve block 26 with a high pressure inlet passage 28 formedtherein which communicates with a riser passage 30. The valve block 26has a moveable expansion valve member 32 disposed therein against avalve seat 34; and, the block has an outlet 36 which communicates withthe valve seat via a passage 38.

[0013] The expansion valve member 32 is moved by an operating member orrod 40 which is intended for connection to a thermally responsive sensor(not shown) such as a fluid filled temperature sensing capsule wellknown in the art.

[0014] The expansion valve member 32, preferably in the form of aspherical member, is biased to the closed position against seat 34 by acap 42 which is contacted by the lower end of a spring 44 which has itsupper end registered against the end of a counter bore formed in anannular retainer 46 which threadedly engages the block as denoted byreference numeral 48. Retainer 46 is rotatable in the threads 48 foradjusting the preload of spring 44 on the expansion valve member 32. Themember 46 has a central passage therethrough denoted by referencenumeral 50 which communicates with the expansion valve seat 34.

[0015] An inlet shutoff valve seat member 52 having a generallycup-shaped configuration is received over the spring retainer 46 andsealed thereover by a seal ring 50. Shutoff valve seat member 52 has apassage 56 formed in the upper end thereof which communicates with aninlet shutoff valve seat 58 formed on the upper end of member 52 andwhich is contacted by the lower end of a shutoff valve member 60.

[0016] Valve member 60 is slidably received in a bore 62 formed in thelower end of an armature 64 which is slidably retained in a tubulararmature guide member 66 which has an enlarged diameter portion 68 whichopens in a radially outwardly extending annular flange 70. The armatureguide member flange 70 is retained in the valve block 26 by a collar 72threaded in the valve block and bearing against the flange 70.

[0017] The interior of the enlarged portion 68 of the armature guide 66forms an annular chamber 71 about member 52, which chamber 71 is in opencommunication with riser passage 54. In the presently preferredpractice, the shutoff valve member 60 has a pilot passage 74 providedtherethrough which has a pilot valve member 76 seated thereon and biaseddownwardly against the upper end of the pilot passage 74 by a spring 78which has its upper end registered against a pole piece 80 secured tothe upper end of the armature guide in a fluid type arrangement as, forexample, by weldment or interference fit.

[0018] Armature 64 forms a working air gap 82 at its upper end with thelower surface of the pole piece 80. A coil bobbin 84 with a coil 86wound thereon is received over the armature guide and retained thereonby a cap 88 secured by a clip 90 pressed over the pole piece 80. Acylindrical casing 92 is received over the coil for completing a fluxloop thereabout. An annular inner flux collector member 94 is providedover the armature guide within the bobbin at the lower end thereof inthe presently preferred construction.

[0019] Upon energization, the coil 86 causes the armature to moveupwardly closing air gap 82 and lifting the pilot valve member 76causing flow from above the main valve member to exit through the pilotpassage 74 thereby reducing the pressure on the upper end of thearmature whereupon pressure forces acting on the lower end of thearmature aid in lifting the shutoff valve member 60 from valve seat 58.Upon lifting of the shutoff valve member 60 from valve seat 58, fluidflows through riser passage 30 and around the valve seat member 52 overvalve seat 58 and through passage 56 through passage 50 in retainer 46to the expansion valve 32.

[0020] Referring to FIG. 2, the shutoff valve seat member 52 is shownwith a diffuser indicated generally at 96 which includes a plurality ofradially extending channels 98, 100, 102, 104 formed in the upper end ofthe member 52 and feeding to the inlet side of the valve seat surface58. Thus, the channels 98, 100, 102, 104 diffuse the flow and tend toreduce turbulence and serve to eliminate undesirable flow noise.Although the diffuser 96 is shown in the form of radial channels orgrooves formed in the upper end of the member 52 in a unitary one-piecearrangement, it will be understood that the diffuser may be configuredotherwise where, for example, channels 96-102 may be formed as bores andmay alternatively be formed in a separate member from member 52.

[0021] The present invention thus provides a unique and novelcombination of a thermal expansion valve and electrically operated inletshutoff valve having a diffuser on the inlet side of the shutoff valveseat to reduce flow noise.

[0022] Although the invention has hereinabove been described withrespect to the illustrated embodiments, it will be understood that theinvention is capable of modification and variation and is limited onlyby the following claims.

1. A thermally responsive expansion valve assembly having anelectrically operated shutoff valve in the inlet thereof comprising: (a)a valve body having an inlet and outlet and an expansion valve membermoveable by an operating member adapted for connection to a thermallyresponsive element for controlling flow between the inlet and outlet;(b) a shutoff valve member disposed between the main valve member andthe inlet; (c) a valve seat member disposed adjacent said shutoff valvemember, said valve seat member having an annular seating surface and adiffuser disposed between said inlet and said annular seating surface;and, (d) a solenoid operator attached to said body and having anarmature operably connected for effecting movement of said shutoff valvemember upon energization of the solenoid.
 2. The valve assembly definedin claim 1, wherein said diffuser includes plurality of radiallyextending passages surrounding said annular seating surface.
 3. Thevalve assembly defined in claim 1, further comprising a pilot valvemember operable, upon energization of the solenoid, for opening a pilotpassage through said shutoff valve member.
 4. The valve assembly definedin claim 1, wherein said annular seating surface and said diffuser areformed integrally in a one piece member.
 5. The valve assembly definedin claim 1, wherein said valve seat member has an inverted cup-shapedconfiguration and said diffuser comprises a plurality of radiallyextending channels formed on the closed end thereof surrounding saidannular seating surface.
 6. A method of making a thermally responsiveexpansion valve assembly having an electrically operated shutoff valvein the inlet thereof comprising: (a) disposing an expansion valve membermoveably in a valve body and disposing an operating member from athermally responsive unit in contact with the expansion valve member,and forming an inlet and outlet in the body communicating with theexpansion valve member; (b) disposing a shutoff valve member and anannular valve seat between the expansion valve member and the inlet; (c)disposing a diffuser adjacent said annular valve seat on the upstreamside thereof; and, (d) disposing a solenoid operator on said valve bodyand energizing the solenoid and moving the shutoff valve member with thesolenoid armature.
 7. The method defined in claim 6, wherein the step ofdisposing a diffuser includes forming a plurality of radially extendingpassages surrounding said annular valve sent.
 8. The method defined inclaim 6, wherein the step of disposing an inlet valve member includesforming a pilot passage in the inlet valve member and disposing a pilotvalve therewith.